Also, JavaScript performance will jump from 0.5 to 0.8 Chromes for sunspider and from 0.25 to 0.6 Chromes for v8bench (arewefastyet.com).

These 30% to 50% jumps in performance shown on arewefastyet.com are merely the jumps in Firefox 4 performance since July 28 to September 15.

They are not the jumps in performance from Firefox 3.6 to Firefox 4, which has seen a performance improvement of over 250% in all.

The speed improvement from gecko 1.9 to Gecko 2, when it is released, will be far more dramatic than the picture you paint.

Having no more features than Chrome and being slower than Chrome

The first is decidedly incorrect, the second is yet to be determined, it is still an open question, except for the performance of rendering and compositing on not-too-old hardware, where Firefox 4 is many times faster than Chrome.